Octopart lets you compare prices across all of them (and more).
For components that you can tolerate the occasional issue with, AliExpress is also a plausible option.
Specifically for tinkering with FPGAs, I'd recommend looking into Numato. They're a small-ish business based out of India that produce cheap and cheerful FPGA boards. The products are well-made and support is great.
For the soldering station, I'd recommend just Googling "Hakko FX-888" and ponying up the US$100 or so to get one from a reputable supplier. There are cheaper products such as the YiHua 936 you can get for, say, $30 that seem similar to the Hakko on the surface, but all of them will break within 2 years while the Hakko will last many decades. If you're just getting started and don't want to drop $100, just stick to the $10 40W pencil irons and you'll be fine.
Whatever route you go, make sure to get good solder (e.g. Multicore). I used cheap DealExtreme solder for repairs back in the day, and after a couple of years all of the joints cracked and I had to re-do them. Some of the stuff had been repaired for friends and I'm sure at least some of it was binned. If you're strapped for cash, I would seriously recommend buying a cheaper soldering iron in order to get good solder.
Final thing, if you're looking for a cheap oscilloscope for getting started, check out EspoTek (disclaimer: I own the business). It's cheap and cheerful, and designed for newbies just getting into the hobby. A lot of effort has been put into the product, and it's still (semi) actively maintained on GitHub.